Parapet Wall - Coping / Repointing

[freddiemercurystwin]

If you stick a tarp over it weighted down on the inside with bricks or whatever on the flat roof and a timber batten stapled or similar to the tarp that overhangs the wall to keep it in position then that may narrow the source of the leak down to just the wall or just the top.

 

[Abyone]

Yeah, well I know I have a leak from the top anyway from my hose tests so that has to be fixed. And I have a plastic cover on kind of as you describe, which has worked.

 

[freddiemercurystwin]

OK so are you getting anymore leaks then? Though your cover doesn't contain that brickwork on the inside.

 

[Abyone]

I'm good I just want to know whats the best thing to do.
Should I repoint or relay the top bricks or just add a plywood base to wall top and fix metal coping over it.

 

[freddiemercurystwin]

Any brickwork/mortar that's not sound should be repointed/fixed irrespective of what else you do, then I would go with epdm over the parpet dressed down over the lead with a suitable flashing on the inside and 50mm or so down on the outside again with a suitable flashing, then fit your coping on top. Or just don't bother with expensive aluminium coping and just do it in epdm and the proper flashings for parapets.

 

[Abyone]

Thanks was thinking of EPDM.
Would i place that direct on top of wall.
No issues with breathability or condensation ?

 

[freddiemercurystwin]

I would have fixed some plywood to the wall first eg

Shouldn't get any issues with condensation.

Once you've repointed all the bricks etc on the parapet it might be enough to stop the leak anyway, as presumably it worked OK until now?

 

[Abyone]

Thanks.
I know the metal will cost a bit more but if it looks the part I don't mind. It at the front of my house so I want it to look as well as possible.inside looking out is less important but I'd still prefer it to look well.

Yeah the repointing might do it, but I had a builder out to look and they were saying just put the coping on and not to bother with the repointing hence me asking all the questions here.

 

[^woody^]

The weep holes aren't the problem though. The water is coming down from above and all of it doesn't go into the tray.

The tray, any tray would cross the cavity and prevent the problem you are describing.

 

[Abyone]

The tray, any tray would cross the cavity and prevent the problem you are describing.

There's nothing I can do with the tray now.

And not sure how a tray seals against the insulation and block work on the inner wall.

The joists protrude the inner block leaf, water can get into the joists and drip off anywhere.
Tray does nothing for that.

 

[datarebal]

water is coming down from above

That's why you have trays .
The tray should not sealed with mastic as here

 

[Abyone]

That's why you have trays .
The tray should not sealed with mastic as here

The tray is embedded in the mortar.
The flashing under the tray is sealed with silicone.
The weep holds are flush with bottom of tray so there is no blockage.

 

[datarebal]

That's good then

 

[^woody^]

There's nothing I can do with the tray now.

And not sure how a tray seals against the insulation and block work on the inner wall.

The joists protrude the inner block leaf, water can get into the joists and drip off anywhere.
Tray does nothing for that.

The thing is, the primary defence against water getting in to the parapet and through the face of the wall above the window is the cavity tray.

Parapets are prone to leaks, and rain can penetrate face brickwork, despite water repellant, and if the tray is not performing you could be back here posting in the future.

So what I can't understand is that even if you took the top of the parapet off, you should not be getting water penetration to the room below if the cavity tray is functioning. And if its not functioning, then you need to be 101% certain that you will be stopping water getting into that cavity.

 

[freddiemercurystwin]

I thought the OP said after applying a temporary cover on top of the parapet his leaks have ceased?